The NSF-supported research icebreaker Laurence M. Gould operates year-round in support of the U.S. Antarctic Program, carrying out global change studies in biological, chemical, physical, and oceanographic disciplines.
This data set consists of underway data from leg LMG1101 on the R/V Laurence M. Gould. This leg started at Punta Arenas, Chile and ended at Punta Arenas, Chile.
The data in this file were collected by a single contractor (CTAM) who were responsible for collecting and processing the data. The data from this survey were collected using the same instruments (magnetometers and navigational systems) throughout the survey and were collected in a normal length of time with no long delays between survey beginning ... and end. Standard industry practices of the time were followed in data collection and processing.
High- resolution horizontal position of the survey aircraft used to collect data were determined from GPS satellites. Positioning data were recorded in-flight independently using a Trimble 4000 and an Ashtech Surveyor 12 receivers. When possible a differential position was calculated. When not an autonomous position was used. Positions were good to one meter when differentially processed and 20 meters when autonomous was used.
The cesium magnetometer is accurate to about 0.002 nanoteslas (nT) at 1 Hz and the proton precession base station magnetometer is accurate to about 1 nT. Therefore the accuracy of the base station corrected data is 1 nT or better.